John Oliver does his best to try to explain how a pathological liar came to occupy the White House on his HBO show “Last Week Tonight.” (Photo: Pool/Getty Images)

President Trump is still struggling with the levers of power, including some fundamental ones, like telling the truth. But John Oliver sets him straight on HBO’s “Last Week Tonight.” He says it’s time to examine “reality itself.”

Trump has been caught in one lie after another since taking office, including whoppers he told on the campaign trail.

He still insists that 3 million to 5 million illegal aliens voted in the election. You may recall, he made that argument when he thought he was going to lose.

But he can’t let the lie die an ignoble death because actually did lose the election to Democratic rival Hillary Clinton by 2.8 million popular votes.

His White House counsel Kellyanne Conway summed up Trump’s version of reality. It’s based on “alternative facts.”

How do you explain that one?

“Normally we like to focus this part of the show on complex depressing policy issues… But unfortunately we can’t until we address something even bigger… the concept of reality itself.”

Since taking office, Trump has made it clear that reality is not important to him. “He even lied about the weather during his inauguration,” he noted.

“So that is where we’re currently at. We have a president capable of standing in the rain and saying it was a sunny day.”

Any policy discussion has to begin with a shared sense of reality, and Trump’s reality can change in a single second, Oliver said.

Keith Girard has 30 years of experience as an award-winning reporter, editor-in-chief, and senior media executive. Keith’s career began in Washington, D.C., where he was a reporter for The Washington Post and a contributing editor for Regardie's and Washingtonian magazines. He also worked as a writer/producer in CNN's Washington Bureau and has written one book on the U.S. Marines in the Gulf War.